
<template>
  <div class="todo-footer" v-show="total">
     <label>
        <input type="checkbox" :checked="isAll" @change="checkAll"/>
     </label>
     <span>
        <span>已完成: {{doneTotal}}</span> /全部：{{total}}
     </span>
     <button class="btn btn-danger" @click="clearAll">清除已完成任务</button>
  </div>
</template>

<script>
    export default {
        name: 'MyFooter',
        props: ["todos", "selectAllTodo", "clearAllTodo"],
        computed: {
            //总数
            total(){
                return this.todos.length
            },

            //已完成数
            // doneTotal(){
            //     let i=0
            //     this.todos.forEach((todo) => {
            //         if(todo.done) i++
            //     });
            //     return i
            // }
            doneTotal(){
                const x = this.todos.reduce((pre, cur) => {
                    return pre + (cur.done ? 1: 0)
                }, 0)
                return x
            },
            //全选框是否勾选
            isAll(){
                return this.doneTotal === this.total && this.total > 0
            }
        },
        methods: {
            checkAll(e){
                // console.log(e.target.checked)
                this.selectAllTodo(e.target.checked)
            },
            clearAll(){
                this.clearAllTodo()
            }
        },
        }
</script>
<style scoped>
  .todo-footer {
    height: 40px;
    line-height: 40px;
    padding-left: 6px;
    margin-top: 5px;
  }

  .todo-footer label {
    display: inline-block;
    margin-right: 20px;
    cursor: pointer;
  }

  .todo-footer label input {
    position: relative;
    top: -1px;
    vertical-align: middle;
    margin-right: 5px;
    }

    .todo-footer button {
        float: right;
        margin-top: 5px;}
</style>